When does Misty go back to her gym?

Before she'll return you need to go to Route 9 and Surf to the Powerplant. There talk to manager there and you'll be told about a stolen generator part. Now head back to Misty's gym. You should bump into a Team Rocket Grunt. Instead of battling he'll just take off. Go after him and challenge him to a Pokemon battle. After the battle go back to the gym and search it for the part. After you find the part take it to the Powerplant and return it. Now head to the end of Route 25 and you'll see Misty on a date. Talk to her and she'll return to the gym. Now all you have to do is go back and challenge her.

On the golden bridge there are to people on a date click the middle of them a tem rocket guy will be there after you battle him go to mistys gym the team rocket guy will be there and if you have not beet the 6 trainers there after the 6 people go on the little hill misty wiil be on her date